Method and device for speed control of an ac motor
CA 2176263 C · Owner: Gutsche, Gottfried J. · Inventors: Gutsche, Gottfried J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method and device are disclosed for speed control of an AC induction motor by means of a control circuit which generate a motor drive voltage consisting of a combination of AC and time-spaced DC pulses. During the occurrence of the time-spaced DC pulses in the motor's AC drive voltage a back EMF suppression network is activated to absorb the motor's generated back EMF energy. A further feature of the invention is a slow down mode where the motor is decelerated from continuous full cycle AC to a requested slow speed setting by means of a higher contend of DC pulses in the AC drive voltage.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed May 10, 1996 and granted November 7, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 10, 2016.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 10, 2018.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.